Below is a collection of essential plugins, all chosen based on their usefulness, quality and popularity.
Google XML Sitemaps
This plugin will generate a special XML sitemap which will help search engines like Google, Bing, Yahoo and Ask.com to better index your blog.
Sitemaps make it easier for search engine crawlers to see the complete structure of your sites and retrieve it more efficiently. Google XML Sitemaps supports all kinds of WordPress generated pages and custom URLs, and also notifies search engines each time you post new content.
Contact Form 7
Easily the most popular free forms plugin out there, Contact Form 7 has racked up more than 16 millions downloads in the WordPress Plugin Repository.
This plugin can manage multiple contact forms, plus you can customize the form and any email content with simple markup. It also include support for AJAX-powered submission, CAPTCHA and Akismet spam filtering.
WordPress Beta Tester
Every serious WordPress user/developer should have WordPress Beta Tester. This plugin automatically updates your install to the latest stable release or bleeding edge nightly so you can test the latest/upcoming version of WordPress and this plugin should not be used on a live site.
Infinite SEO is our powerful WordPress SEO plugin. It allow you to easily boost your site’s ranking through comprehensive and powerful site maps, and title and meta data optimisation, as well as automatic site-wide linking and complete Moz integration.
This popular free plugin allows you to duplicate, clone, backup, move and transfer an entire site from one place to another.
Duplicator is made by developers for developers. It’s a great tool for pulling a production site down onto a local machine for testing, as well as the reverse – developing locally and pushing a site to a production server.
Duplicator has racked up more than 480,000 downloads and has received an average rating of 4.9 stars on the WordPress Plugin Repository. Duplicator gets a thumbs up from me, too. This is a great plugin.